-LRB- CNN -RRB- -- After receiving nearly 100 reports of stuck gas pedals in Ford and Mazda vehicles , federal regulators said Tuesday they have launched an investigation into the problem , which is a suspected cause of one death and nine injuries .

The stuck accelerators are being investigated for their possible role in one fatal accident , 13 nonfatal crashes or fires and eight injury accidents , according to the National Highway Transportation Safety Administration .

Ford and Mazda said 591,245 vehicles were potentially affected , according to the automakers ' reports to the NHTSA in 2004 . More than half the vehicles were 2001-2004 model year Ford Escapes . The remaining vehicles were 2001-2004 Mazda Tributes .

The NHTSA now has identified 730,000 vehicles potentially affected , expanding the scope of vehicles in question . All 730,000 are 2001-2004 Ford Escape and Mazda Tribute SUVs with V6 engines , according to the NHTSA .

Mazda and Ford issued recalls in 2004 on models of the sport utility vehicles that had 3.0 liter six cylinder engines . Several of the reports to the NHTSA involve vehicles not covered by previous recalls , the agency said in a letter to Ford 's Environmental and Safety Compliance Global Director on Thursday .

One complaint is based on a fatal crash that occurred in January 2012 , the NHTSA said . Some of the complaints allege that failures may have been related to repairs made in response to safety recalls initiated in 2004 , the investigation summary said .

The 2004 Ford and Mazda recalls were for the vehicle speed control cables in their affected vehicles . Letters were also sent to dealers and customers , according to filings on the NHTSA website .

`` On your vehicle , it is possible that the accelerator cable may prevent the throttle from returning to the idle position , possibly resulting in elevated engine speeds while driving , '' Ford 's letter to customers read . `` An unexpected increase in engine idle speed may increase stopping distance and may result in a vehicle crash without warning . ''

The Center for Auto Safety petitioned the NHTSA to open a similar investigation on July 8 . The petition was denied Thursday because part of the request is being covered by the agency 's newly opened investigation .

The NHTSA has opened the investigation to assess `` the scope , frequency and safety-related consequences of the alleged defect , '' the agency said .

Neither Ford nor Mazda responded to CNN 's requests for comment .

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NHTSA has received nearly 100 reports of stuck gas pedals

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Ford and Mazda issued some recalls for the problem in 2004

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Problem suspected in one death , nine injuries